Field of the Invention
The present invention relates to a machine tool.
Discussion of the Background
FIGS. 16 and 17 illustrate a conventional mechanism. A machine tool 1 includes a pallet change unit 20 on the front side of a main machine 10. The main machine 10 includes a table 12. The pallet change unit 20 includes a pallet change base 21, a pallet change slider 22, and a pallet turning arm 23. The pallet change slider 22 reciprocates on the pallet change base, and the pallet turning arm 23 makes turning. By these movements, pallets 24 are replaceably supplied to the table 12. A main body cover 26 covers the pallet change unit 20. On a side surface of the main body cover 26, a sliding door 30 is disposed. The sliding door 30 is openable and closable in arrow K directions. In the case where an operator enters a work area E2, the operator pulls out a plug switch 62 inserted in the switch panel 60 after the pallet turning arm 23 is turned from an operating position to an evacuating position illustrated in FIG. 17 with the pallet change slider 22 stationary at a setup position F. As a result, the power source to the pallet change unit 20 is shut off, and a door lock switch, not illustrated, between the sliding door 30 and a cover 15 of the main machine is unlocked. Next, the operator opens the sliding door 30 to enter an internal passage area E1, and opens an operator door 50 of the main machine to move into the work area E2. With the plug switch 62 pulled out, an interlocking mechanism is in operation to keep the power source of the pallet change unit 20 off even if the sliding door 30 is closed. The operator carries the plug switch 62 when entering the internal passage area E1 or the work area E2. This ensures that the power source of the pallet change unit 20 will not be turned on even if another operator attempts to turn on the power source while the former operator stays in the internal passage area E1 or the work area E2. In this manner, safety of the operator is ensured.
Japanese Unexamined Utility Model Application Publication No. 06-042044 and Japanese Unexamined Patent Application Publication No. 2000-045664 are incorporated herein by reference in their entirety.